The MUTCD doesn't require square corners on signs. But it does give the option that sign panel area outside the rounded border edges may be trimmed. I think most states just don't do this because it's not worth the extra time/expense.

The MUTCD doesn't require square corners on signs. But it does give the option that sign panel area outside the rounded border edges may be trimmed. I think most states just don't do this because it's not worth the extra time/expense.

It usually has to do with the type of sign (extruded vs incremental panels) but I believe New York has a rule or law that the corners have to be rounded for safety issues, to avoid a hazard for sign installers.